Calculator



0. NELSON CALCULATOR Jan. 2, 1940.

Filed July 1, 1938 2 Sheets-Sheet l Inventor Oscar Nelson Attorneys Jan. 2, 1940.

0. NELSON Filed July 1, 1938 2 Sheets-Sheet 2 Oscar Nelson Aiiomcgs Patented Jan. 2, 1940 UNITED STATES, PATENT orrica 1 Claim.

My invention relates generally to calculators operating on a logarithmic slide rule principle, and particularly to a calculator of this type which involves concentrically arranged scales and rela- 5 tively movable circular elements in conjunction with radial pointers, and an important object of my invention is to provide a simple and efficient calculator useful for quickly ascertaining the answers to a variety of mathematical problems.

10 p. Another-important object of my invention is to provide a calculator of the character indicated above which involves a minimum of sturdy parts, and is capable of being constructed at a low cost.

Other important objects and advantages of the 18 invention will be apparent from a reading of the following description taken in connection with the drawings, wherein for purposes of illustration I have shown a preferred embodiment of my inven- 'tion.

20 In the drawings:

Figure 1 is a side elevational view of a preferred embodiment.

Figure 2 is an enlarged transverse vertical sectional view taken through the table portion of 25 the embodiment.

Figure 3 is an enlarged sectional view taken through Figure 2 approximately on the line 33.

Figure 4 is a plan view of the table portion showing the various scales and the inter-relation 80 thereof.

Referring in detail to the drawings, the numeral 5 generally designates the embodiment which consists of some suitable form of support which is generally designated 6 and which in the 85 present instance comprises a standard for resting on a surface provided with an upper portion cut at an acute angle and topped by the table I on which is secured by suitable means the outer rotatable scale bearing annulus 8 and the inner 40' stationary scale bearing disk 9, the disk 9 being of a size to fit rotatably in the opening of the annulus. Radial pins l fixed at circumferentially spaced points on the annulus 8 and projecting from the radially inward edge of the annulus engage in the circumferential groove ll formed in the edge of the disk 9.

Penetrating square holes in the table I, and the disk 8 at the center thereof is the bolt I2 50 which is provided with an enlarged squared shank l3 and a head l4 engaging the bottom of the table I, the said shank extending through the disk 8 and at the top of the disk having a reduced rounded shank l5 which has a short threaded portion receiving the clamping nut l8.

Circumposed on the rounded shank l5 next to the disk 9 is the'spacer H and next above the transparent pointer or indicator l8 and above this the spacer l9 and above the spacer IS the transparent pointer or indicator 20, and above this the retainer washer 2| which is directly engaged by the nut l6.

The transparent indicator [8 has its radially outward end traversed by a screw 22 which passes through a spacer 23 and into the annulus 8 at a 10:

point radially inwardly spaced from the peripheral edge of the annulus, thereby securing the indicator l8 for movement with the annulus 8. The transparent indicator has its radially out ward end set into and attached to a support 23 II for the roller 24 which rolls on the top of the annulus 8 adjacent the peripheral edge thereof and in a path located beyond the radially outward end of the indicator l8 as clearly shown in Figures land 2, whereby the indicator 20 may be 20 swung around the pivot bolt I! as required for the calculations.

Referring now to Figure 4 of the drawings it will be seen that the surface of the annulus 8 and the disk 9 are laid out with circular scales with 25 which the indicators l8 and 28 cooperate. The outermost scale A on the annulus 8 is a protractor and day scale, and reading radially inwardly, the next scale B is a square root scale and corresponds with scale C so that the square root of any 30 number can be read from scale C.

The scale A-is simply a circle marked into 360 equal divisions to work with scale E on the stationary disk 9 which is so related thereto that January 2nd will correspond with l on scale A. 5 There is a slight overlapping at the end of the year which can be put into the lower side of the January column.

The scale D, being the outermost scale on the stationary disk 9, is identical with scale C, both being used in multiplication and division.

The next inner scale is scale E already mentioned and immediately within this is the scale F which is a sine value scale which is related to scale D when the indicator is placed over any angle on the scale F.'

The next inner scale is G which is divided into 365 days of the year and is arranged for use with scale C to show the fraction of the year for any given number of days in a year of 365 days.

The next inner scale is H which is a tangent scale and is related to the scale D so that the tangent values can be read on scale D for any angle on scale H.

Operation 0/ the calcldator To multiply the stationary indicator II is set, by rotating the annulus l. on a numeral on the scale D. The product will then be found on scale D opposite the multiplier on scale C.

To divide the multiplication operation is simply reversed, the quotient being found under the stationary indicator II.

The number of days subtended by two given dates can be ascertained by using the revolving indicator 20 and reading the answer on scale A.

To find the date from which a given number of days has been subtracted, the operation described immediately above is simply reversed.

To ascertain sine values of angles the scale F is used with the scale D.

By using scale H with scale D tangent values can be ascertained.

By using scale G with scale D any traction of a year can be ascertained, for use in calculating interest on money.

By using diflerent combinations of the described scales computations in various types of problems can be accomplished. The dual indicator arrangement oi the present invention is especiallyhelpful in that it enables the operator of the calculator to read answers readily, quickly, and accurately.

Although I have shown and described herein a preferred embodiment 0! m invention, it is to be definitely understood that I do not desire to limit the application of my invention thereto, and any change or changes can be made in the structure and arrangement of the parts within the spirit of the invention and the scope of the subjoined claim.

Having described the invention, what is claimed as new is:

A calculator of the character described, said calculator comprising a base, a stationary circular disk resting on said base, an annularplate rotatably resting on said base around said disk, means retaining said annular plate on said base, an element passing non-rotatably through the centers of said base and said disk to a point above said' disk, said element having an enlarged head engaging the bottom or said base, the part oi said element above said disk being rounded, a pair of indicators extending across said disk and said annular plate, saidindicators having their radially inward ends pivoted on said rounded part of said element, means vertically spacing said indicators on said part, and retaining means con nected to the end of said element opposite said enlarged head and cooperating with said head in assembling said base, said circular disk and said indicators together.

OSCAR NELSON. 

